This invention relates generally to cooling systems and more particularly to two stage cooling systems.
Two stage cooling systems are well known in the art and have been used for many years. Their usage in extense is well documented in the book, Evaporative Airconditioning, by John R. Watt, put out by The Industrial Press, (copyright 1963).
Basically, a two stage cooling system utilizes a first evaporative cooler to pre-cool the incoming air without increasing it's moisture content. This pre-cooled air is then passed on to the second stage which utilizes another evaporative cooler to further cool the air to a lower temperature.
A description of a two stage evaporative cooler is made by U.S. Pat. No. 3,521,460 issued to James A. Knowles on July 21, 1970. The Knowles patents pre-cools the outside air which is then further cooled by local stations within the interior of the building. In the Knowles patent, the cooling medium is chilled water. The cooling affect of the chilled water is made through heat exchangers in each location within the building.
Two primary restraints exists upon the current state of the art of a two stage cooler: the first being that the cost of a heat exchanger is commercially prohibitive. The second limitation is that a heat-exchange develops calcium carbonate or scaling which diminishes its effectiveness.
It is clear from the foregoing, that the present systems are either inefficent, or uneconomical for the tasks at hand.